fix(storage): rate limit bucket deletion in cleanup

[abhinavgautam01]

Fixes #5219

Problem

When there are many stale buckets in integration tests, the cleanup process
was deleting them in parallel and exceeding GCP's Storage API rate limit
(approximately one request every two seconds).

Solution

Serialize bucket deletion by removing parallel spawning (tokio::spawn and
join_all) and instead delete buckets sequentially with a 2-second delay
between each deletion to respect the API rate limit.

Changes

• Changed cleanup_stale_buckets() to delete buckets sequentially
• Added 2-second delay between bucket deletions
• Maintains proper error handling for each deletion attempt
• Delay is not applied after the last bucket (no unnecessary wait)

Testing

This change should prevent rate limit errors during stale bucket cleanup
in integration tests.

[gemini-code-assist]

Code Review

This pull request modifies the cleanup_stale_buckets function in the storage examples to serialize bucket deletions. The implementation replaces concurrent task spawning with a sequential loop that introduces a 2-second delay between deletions to comply with GCP rate limits. Feedback was provided to replace println! calls with the tracing crate to align with the repository's structured logging standards.

[coryan]

/gcbrun

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.92%. Comparing base (aaabe4e) to head (15dadf5).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5612   +/-   ##
=======================================
  Coverage   97.92%   97.92%           
=======================================
  Files         221      221           
  Lines       52759    52759           
=======================================
+ Hits        51662    51663    +1     
+ Misses       1097     1096    -1     

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[abhinavgautam01]

ping @coryan

[coryan]

/gcbrun

[coryan]

Formatting is failing with:

diff --git a/src/storage/examples/src/lib.rs b/src/storage/examples/src/lib.rs
index 6c42795..22eedff 100644
--- a/src/storage/examples/src/lib.rs
+++ b/src/storage/examples/src/lib.rs
@@ -23,10 +23,8 @@ use google_cloud_gax::options::RequestOptionsBuilder;
 use google_cloud_gax::paginator::ItemPaginator as _;
 use google_cloud_gax::throttle_result::ThrottleResult;
 use google_cloud_gax::{
-    backoff_policy::BackoffPolicy,
-    error::rpc::Code,
-    exponential_backoff::ExponentialBackoffBuilder,
-    retry_policy::RetryPolicyExt,
+    backoff_policy::BackoffPolicy, error::rpc::Code,
+    exponential_backoff::ExponentialBackoffBuilder, retry_policy::RetryPolicyExt,
     retry_state::RetryState,
 };
 use google_cloud_storage::client::{Storage, StorageControl};

Remember to always use cargo format from the top-level directory so the configuration takes effect. I think in this case cargo format -p storage-samples would fix the problem.

[abhinavgautam01]

Formatting is failing with:

diff --git a/src/storage/examples/src/lib.rs b/src/storage/examples/src/lib.rs
index 6c42795..22eedff 100644
--- a/src/storage/examples/src/lib.rs
+++ b/src/storage/examples/src/lib.rs
@@ -23,10 +23,8 @@ use google_cloud_gax::options::RequestOptionsBuilder;
 use google_cloud_gax::paginator::ItemPaginator as _;
 use google_cloud_gax::throttle_result::ThrottleResult;
 use google_cloud_gax::{
-    backoff_policy::BackoffPolicy,
-    error::rpc::Code,
-    exponential_backoff::ExponentialBackoffBuilder,
-    retry_policy::RetryPolicyExt,
+    backoff_policy::BackoffPolicy, error::rpc::Code,
+    exponential_backoff::ExponentialBackoffBuilder, retry_policy::RetryPolicyExt,
     retry_state::RetryState,
 };
 use google_cloud_storage::client::{Storage, StorageControl};

Remember to always use cargo format from the top-level directory so the configuration takes effect. I think in this case cargo format -p storage-samples would fix the problem.

Good catch — ran the formatter from the repo root with cargo fmt -p storage-samples so the workspace rustfmt config applies; it collapsed the google_cloud_gax import list to match the diff you pasted.

[coryan]

/gcbrun

[coryan]

/gcbrun

[coryan]

This is looking good, I need a review from somebody in the @googleapis/gcs-team